This invention relates to the automatic control of artificial light in a room to prevent the inefficient use of electric power in little used areas of one's home or business. The most commonly used means for disrupting the electric power to an electric light consist of passive mechanical contactors (switches) requiring human intervention. Active devices used to disable electric lights are also available (some of which utilize optical emitters--sensors to control the artificial illumination in a room), however none of these units have the necessary entry/exit logic of the device of this invention. Less sophisticated controllers that turn room lights off unless overridden by periodic human intervention also exist. Most of these devices, like mechanical switches, have as their primary purpose the reduction of electric power consumption during periods when either artificial illumination is not required or the area in question is not in use.
It would be useful to have a device that would turn on a room electric light when it is entered and maintain the light in the on-state as long as the room is occupied unless manually overridden. A device whose energy consumption per unit time would be very small when compared to that consumed by commonly used light bulbs per unit time. It would be particularly useful to have a device to turn lights off in unoccupied restrooms and other public rooms in business establishment (e.g. copy rooms without relying on human intervention).
It is an object of the present invention to provide a device to maintain the artificial illumination of a room in the off-state when it is unoccupied and to maintain the artificial illumination in the room in an on-state during periods of human residency.
It is further object of the present invention to provide an automatic room light controller for attachment to doorways. Other objects will become apparent in the course of a detailed description of the invention.